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Search: id:A073124
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| A073124 |
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a[n]=prime[1+prime(n)]-prime[prime[n]]. |
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+0
8
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| 2, 2, 2, 2, 6, 2, 2, 4, 6, 4, 4, 6, 2, 2, 12, 10, 4, 10, 6, 6, 6, 8, 2, 2, 12, 10, 6, 6, 2, 2, 10, 4, 14, 12, 4, 4, 10, 4, 6, 2, 6, 4, 10, 10, 12, 6, 4, 14, 6, 4, 10, 12, 8, 4, 6, 24, 10, 6, 2, 8, 14, 18
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of entries in {x,..} such that PrimePi[x]=Prime[n].
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FORMULA
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a(n) = Card{x; A000720(x) = A000040(n)}
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EXAMPLE
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n = 25: p(25) = 97, Pi[x] = 97 holds for 12 numbers: X = {509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520} so a(25) = 12. Largest 520 = A073123(25), smallest = A006450(25).
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MATHEMATICA
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Table[Prime[Prime[n]+1]-Prime[Prime[n]], {n, 1, 256}]
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CROSSREFS
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Cf. A000720, A000040, A006450, A073123.
a[n]=A072677(n)-A006450(n)
Sequence in context: A079894 A114005 A103794 this_sequence A070877 A156717 A130754
Adjacent sequences: A073121 A073122 A073123 this_sequence A073125 A073126 A073127
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 16 2002
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